The actual tax proposed by Texas legislature is well below $500 as well. But the OP's math skills are severely lacking.
But, as I explained earlier in the thread, if an ICE vehicle gets 25mpg, and the average price of regular unleaded is $3.21, it costs $0.13 per mile to drive. If the cost of electricity in Texas is between $0.101 and $0.12 per Kw hr, it costs between $0.03 and $0.04 per mile top operate. (And this does not include oil changes)
If the drivers drive the US average of 12,000 miles per year, the EV driver pays between $360 and $480 per year for the energy to do it. An ICE driver, getting 25mpg, will spend $1,560 per year for the energy to do it. Tacking $400 onto the higher priced electrical rate will still only be $880 per year to drive 12,000 miles. Well below what the ICE driver spends, especially if you add in oil changes every 3k milles.